Animal Heritage is a historical and ethnographic study of architects who build structures for urban human-animal co-habitation. Around the world, climate change, economic development, and other anthropogenic forces have driven animals out of their native habitats and into human-dominated cities. In the United States, a league of architects has mobilized under the banner of “habitecture”—a portmanteau of “habitat” and “architecture”—to design built environments that are sensitive to animal phenomenologies (how animals perceive, construct, and navigate spaces). By pairing 20th century histories of architecture for animals with ethnographic fieldwork at three studios where habitecture is practiced, this book project analyzes how this “ethological turn” in architecture decenters the human as the arbiter of heritage. While scholars have recognized built environments as sites in which heritage is both placed and produced, Animal Heritage considers the emergence of habitat as a shifting domain of synanthropic heritage. How do architects create the made into a mesh of more-than-human significance? Which animals are included, and which are excluded, from the fold of memory, dwelling, and belonging? Through attention to questions such as these, I offer not just a posthuman critique of our anthropological theories of heritage but also a framework for living justly in multispecies communities.